Add cross-platform support to decky (#387)

* Import generic watchdog observer over platform specific import

* Use os.path rather than genericpath

* Split off socket management in plugin.py

* Don't specify multiprocessing start type

Default on linux is already fork

* Move all platform-specific functions to seperate files

TODO: make plugin.py platform agnostic

* fix import

* add backwards compat to helpers.py

* add backwards compatibility to helpers.py harder

* Testing autobuild for win

* Testing autobuild for win, try 2

* Testing autobuild for win, try 3

* Testing autobuild for win, try 4

* Create the plugins folder before attempting to use it

* Implement win get_username()

* Create win install script

* Fix branch guess from version

* Create .loader.version in install script

* Add .cmd shim to facilitate auto-restarts

* Properly fix branch guess from version

* Fix updater on windows

* Try 2 of fixing updates for windows

* Test

* pain

* Update install script

* Powershell doesn't believe in utf8

* Powershell good

* add ON_LINUX variable to localplatform

* Fix more merge issues

* test

* Move custom imports to main.py

* Move custom imports to after __main__ check 

Due to windows' default behaviour being spawn, it will spawn a new process and thus import into sys.path multiple times

* Log errors in get_system_pythonpaths() and get_loader_version() + 

split get_system_pythonpaths() on newline

* Remove whitespace in result of get_system_pythonpaths()

* use python3 on linux and python on windows in get_system_pythonpaths()

* Remove fork-specific urls

* Fix MIME types not working on Windows

backend/loader.py

@@ -13,7 +13,6 @@ from watchdog.observers import Observer
 from injector import get_tab, get_gamepadui_tab
 from plugin import PluginWrapper
 
-
 class FileChangeHandler(RegexMatchingEventHandler):
     def __init__(self, queue, plugin_path) -> None:
         super().__init__(regexes=[r'^.*?dist\/index\.js$', r'^.*?main\.py$'])